FR4 is a widely used composite material in printed circuit board (PCB) manufacturing. It is composed of woven glass fiber fabric and epoxy resin, which together create a strong, durable, and reliable substrate. The name “FR4” stands for Flame Retardant Level 4, indicating its excellent fire resistance, which is a key requirement in electronics. One of the critical characteristics o... https://www.pcbhamal.com/what-is-fr4-substrate/